[#31] Refactor and simplify CLI

Resolves #31

.gitattributes

@@ -0,0 +1 @@
+dr-cabal-debug.json linguist-generated=true

README.md

@@ -99,8 +99,8 @@ follow these steps:
 > rm -rf ~/.cabal
 > ```
 >
-> A less invasive approach is to point Cabal to a fresh store folder, 
-> but in this case you won't see the `Downloading` phase in the profiling 
+> A less invasive approach is to point Cabal to a fresh store folder,
+> but in this case you won't see the `Downloading` phase in the profiling
 > output:
 >
 > ```shell

dr-cabal.cabal

@@ -81,11 +81,12 @@ library
   exposed-modules:
     DrCabal
       DrCabal.Cli
-      DrCabal.Interactive
+      DrCabal.Json
       DrCabal.Model
       DrCabal.Profile
         DrCabal.Profile.Format
         DrCabal.Profile.Stacked
+      DrCabal.Terminal
       DrCabal.Watch
 
   build-depends:

src/DrCabal.hs

@@ -14,16 +14,12 @@ module DrCabal
     ) where
 
 import DrCabal.Cli (Command (..), readCommand)
-import DrCabal.Interactive (runInteractive)
 import DrCabal.Profile (runProfile)
-import DrCabal.Watch (runWatch)
 
 
 main :: IO ()
 main = readCommand >>= runDrCabal
 
 runDrCabal :: Command -> IO ()
 runDrCabal = \case
-    Watch args       -> runWatch args
-    Profile args     -> runProfile args
-    Interactive args -> runInteractive args
+    Profile args -> runProfile args

src/DrCabal/Cli.hs

@@ -15,32 +15,31 @@ module DrCabal.Cli
     ( Command (..)
     , readCommand
 
-    , WatchArgs (..)
     , ProfileArgs (..)
-    , InteractiveArgs (..)
+    , FileMode (..)
     ) where
 
 import DrCabal.Model (Style (..))
 
 import qualified Options.Applicative as Opt
 
 data Command
-    = Watch WatchArgs
-    | Profile ProfileArgs
-    | Interactive InteractiveArgs
-
-newtype WatchArgs = WatchArgs
-    { watchArgsOutput :: FilePath
-    }
+    = Profile ProfileArgs
 
 data ProfileArgs = ProfileArgs
-    { profileArgsInput :: FilePath
-    , profileArgsStyle :: Style
+    { profileArgsStyle    :: Style
+    , profileArgsFileMode :: FileMode
     }
 
-newtype InteractiveArgs = InteractiveArgs
-    { interactiveArgsStyle :: Style
-    }
+data FileMode
+    -- | Don't read from the file and don't store the results in the file
+    = None
+
+    -- | Store current results in the file
+    | Output FilePath
+
+    -- | Read previously saved results from the file
+    | Input FilePath
 
 readCommand :: IO Command
 readCommand = Opt.execParser opts
@@ -53,48 +52,44 @@ readCommand = Opt.execParser opts
 
 -- | All possible commands.
 commandP :: Opt.Parser Command
-commandP = Opt.subparser (mconcat
-    [ Opt.command "watch"
-          $ Opt.info (Opt.helper <*> watchP)
-          $ Opt.progDesc "Watch cabal output and save it"
-    , Opt.command "profile"
-          $ Opt.info (Opt.helper <*> profileP)
-          $ Opt.progDesc "Output pretty cabal profile results"
-    ]) <|> interactiveP
-
-watchP :: Opt.Parser Command
-watchP = do
-    watchArgsOutput <- Opt.strOption $ mconcat
-        [ Opt.long "output"
-        , Opt.short 'o'
-        , Opt.metavar "FILE_PATH"
-        , Opt.help "Save cabal output to a file in a JSON format"
-        ]
-
-    pure $ Watch WatchArgs{..}
+commandP = Opt.subparser $ mconcat
+    [ Opt.command "profile"
+        $ Opt.info (Opt.helper <*> profileP)
+        $ Opt.progDesc "Build profiling report"
+    ]
 
 profileP :: Opt.Parser Command
 profileP = do
-    profileArgsInput <-  Opt.strOption $ mconcat
-        [ Opt.long "input"
-        , Opt.short 'i'
-        , Opt.metavar "FILE_PATH"
-        , Opt.help "Read profile input from a JSON file, created by 'dr-cabal watch'"
-        ]
-
-    profileArgsStyle <- stackedP <|> pure Stacked
+    profileArgsStyle <- styleP
+    profileArgsFileMode <- fileModeP
 
     pure $ Profile ProfileArgs{..}
 
-interactiveP :: Opt.Parser Command
-interactiveP = do
-    interactiveArgsStyle <- stackedP <|> pure Stacked
+styleP :: Opt.Parser Style
+styleP = stackedP <|> pure Stacked
+  where
+    stackedP :: Opt.Parser Style
+    stackedP = Opt.flag' Stacked $ mconcat
+        [ Opt.long "stacked"
+        , Opt.short 's'
+        , Opt.help "Format as stacked"
+        ]
 
-    pure $ Interactive InteractiveArgs{..}
+fileModeP :: Opt.Parser FileMode
+fileModeP = inputP <|> outputP <|> pure None
+  where
+    inputP :: Opt.Parser FileMode
+    inputP = fmap Input $ Opt.strOption $ mconcat
+        [ Opt.long "input"
+        , Opt.short 'i'
+        , Opt.metavar "FILE_PATH"
+        , Opt.help "Read profile input from a JSON file, created by 'dr-cabal profile --output=<some-file>'"
+        ]
 
-stackedP :: Opt.Parser Style
-stackedP = Opt.flag' Stacked $ mconcat
-    [ Opt.long "stacked"
-    , Opt.short 's'
-    , Opt.help "Format as stacked"
-    ]
+    outputP :: Opt.Parser FileMode
+    outputP = fmap Output $ Opt.strOption $ mconcat
+        [ Opt.long "output"
+        , Opt.short 'o'
+        , Opt.metavar "FILE_PATH"
+        , Opt.help "Save cabal output to a file in a JSON format"
+        ]

src/DrCabal/Json.hs

@@ -0,0 +1,39 @@
+{- |
+Module                  : DrCabal.Json
+Copyright               : (c) 2022 Dmitrii Kovanikov
+SPDX-License-Identifier : MPL-2.0
+Maintainer              : Dmitrii Kovanikov <kovanikov@gmail.com>
+Stability               : Experimental
+Portability             : Portable
+
+This module contains functions to process JSON entries recognised by @dr-cabal@.
+-}
+
+module DrCabal.Json
+    ( readEntries
+    , writeEntries
+    ) where
+
+import Data.Aeson (eitherDecodeFileStrict')
+import Data.Aeson.Encode.Pretty (encodePretty)
+
+import DrCabal.Model (Entry)
+
+import qualified Colourista
+
+
+{- | Read a list of entries from a JSON file.
+
+Exits process with an error message on decoding failure.
+-}
+readEntries :: FilePath -> IO [Entry]
+readEntries file = eitherDecodeFileStrict' file >>= \case
+    Right entries -> pure entries
+    Left err -> do
+        Colourista.errorMessage $ "Error parsing file: " <> toText file
+        Colourista.redMessage   $ "      " <> toText err
+        exitFailure
+
+-- | Write entries as a pretty JSON to the output file.
+writeEntries :: FilePath -> [Entry] -> IO ()
+writeEntries outputPath = writeFileLBS outputPath . encodePretty

src/DrCabal/Model.hs

@@ -14,10 +14,14 @@ module DrCabal.Model
     , Line (..)
     , Status (..)
     , Entry (..)
+    , parseLine
     ) where
 
 import Data.Aeson (FromJSON (..), ToJSON (..), object, withObject, withText, (.:), (.=))
 
+import qualified Data.Text as Text
+
+
 data Style = Stacked
 
 data Line = Line
@@ -62,3 +66,20 @@ instance FromJSON Entry where
         entryStart   <- o .: "startTime"
         entryLibrary <- o .: "library"
         pure Entry{..}
+
+parseLine :: Line -> Maybe Entry
+parseLine Line{..} = do
+    let txtLine = decodeUtf8 lineLine
+    txtStatus : library : _ <- Just $ words txtLine
+
+    -- parse status string to the 'Status' type
+    status <- readMaybe $ toString txtStatus
+
+    -- check if this line is a library: '-' separates library name and its version
+    guard $ Text.elem '-' library
+
+    pure $ Entry
+        { entryStatus  = status
+        , entryStart   = lineTime
+        , entryLibrary = library
+        }